title: Factors affecting vesicle formation and acetylene reduction (nitrogenase activity) in Frankia sp. CpI1.
abstract: Vesicle formation and acetylene reduction (nitrogenase activity) were observed when washed hyphae from cultures of Frankia sp. CpI1 were transferred to a nitrogen-free medium containing ethylenediaminetetraacetic acid and succinate.  Succinate could be replaced by malate or fumarate, but not other carbon sources.  Maximum acetylene reduction and vesicle numbers were observed at a pH of 6.0-6.5, at 25-30 degrees Centigrade, and at atmos pheric Po2 or somewhat less (5-20 kPa).  Addition of 1 mM NH4Cl almost completely inhibited vesicle formation and acetylene-reducing activity, but did not immediately inhibit such reducing activity by cultures with preexisting vesicles.  Acetylene-reducing activity was never observed in the absence of vesicle formation.
mesh_terms: D000114:Acetylene / Q000378:metabolism; D003470:Culture Media; D004492:Edetic Acid / Q000494:pharmacology; D005658:Fungi / Q000201:enzymology* / Q000648:ultrastructure; D006863:Hydrogen-Ion Concentration; D009591:Nitrogenase / Q000378:metabolism*; D009940:Organoids / Q000648:ultrastructure; D010100:Oxygen / Q000494:pharmacology; D013386:Succinates / Q000494:pharmacology; D019802:Succinic Acid; D013696:Temperature
chemical_list: D003470:Culture Media; D013386:Succinates; D004492:Edetic Acid; D019802:Succinic Acid; D009591:Nitrogenase; D000114:Acetylene; D010100:Oxygen